1. Field of the Invention
The present invention relates to a copying device which is capable of carrying out copying on both surfaces of a copying paper or a multiple copying on one surface of the copying paper, in particular to a copying device which can prevent a jamming of papers in both surface copying or a multiple copying.
2. Description of the Prior Art
In a copying device for carrying out a copying on both sides of the copying paper (referred to as the two-sided copying hereinafter) or a multiple copying on the same side of the copying paper, it is at least necessary, after temporarilly collecting the copying papers that were once subjected to the copying process in an internal temporary collecting unit or the like, without ejecting them immediately to the outside, to feed them back again to the image copying unit, by turning them over, in the case of two-sided copying, in order to prepare the reverse sides to another copying, and to feed them without turning them over, in the case of multiple copying, in order to prepare the same sides to the copying of another image. However, the capacity of the temporary collection is limited naturally subject to the overall size of the copying device, limiting the number of sheets of copying papers that can be collected in the temporary collecting unit. For this season, if the copying papers are collected in the temporary collecting unit beyond the limited number of sheets, them the copying device will give rise to a paper jamming.
Now, there are two ways by which manuscripts can be supplied to the copying device. Namely, one is due to automatic supply function in which a sheet out of a plurality of sheets of manuscript that are placed on the manuscript stand is supplied sheet by sheet completely automatically, while the other is due to semi-automatic function in which out of a plurality of sheets of manuscript that are placed on the manuscript stand one sheet is supplied for each operation of the start button, the machine stops after completion of copying of each page of manuscript, and requires another operation of the start button for the next supply and copying of the manuscript page. In carrying out two-sided copying or multiple copying by the use of a copying device that is equipped with such an automatic and a semi-automatic supply functions, if the manuscripts are supplies automatically by means of, for example, the automatic supply function, it may happen that there are collected in the temporary collecting unit copying papers that exceed the number of sheets that can be accomodated, as a result of colection of the copying papers that copied all of the pages of the manuscripts placed on the manuscript stand, regardless of the number of copying papers collectable in the temporary collecting unit, which leads to the problem that gives rise to a jamming of the papers. In addition, when the manuscripts are supplied by the automatic supply function, the manuscripts will be supplied continuously one page after another so that there is also a problem that two-sided copying or multiple copying that is desired by the operator may find it difficult to be achieved freely for each copying.